The Medical Need
The “Back to Sleep” campaign has been a great success, reducing the number of infant deaths from Sudden Infant Death syndrome (“SIDS) by 25% since its inception in 1992. By one estimate, the risk of death due to SIDS is two times greater while sleeping in a prone position than when the child lies in a supine position. Perhaps then, it not surprising that for infants sleeping in a prone position the death rate declined from 70% in 1992 to 24% in 1996 [National Center for Health Statistics, Center for disease Control and Prevention].
Along with positional advice, the American Academy also recommends avoiding soft and gas trapping surfaces in cribs and eliminating “tummy time” while the infant is awake. Under certain circumstances (such as gastroesophageal reflux, upper respiratory tract obstructions or infectious diseases, etc), a pediatrician may weigh the risks and recommend a prone position. However, one side effect of the “Back to Sleep” campaign has been the marked rise of plagiocephaly, and deformational posterior plagiocephaly in particular [Pollack et al., “Diagnosis and Management of Posterior Plagiocephaly”, Pediatrics, Vol. 99, No. 2, February 1997].
The Problem of Plagiocephaly:
Plagiocephaly typically progresses most in infants ranging between birth and 3-4 months of age. Deformational posterior plagiocephaly is a localized flattening of the cranium, usually near the occiput. This pathological condition is illustrated by FIGS. 1A and 1B respectively.
As seen therein, FIG. 1A provides an overhead view of an infant with deformational plagiocephaly; and FIG. 1B schematically illustrates the positional deformation of the soft infant cranium causing unilateral flattening in the parieto-occipital region, anterior advancement of the ipsilateral ear, and associated anterior displacement of the ipsilateral forehead.
Deformational posterior plagiocephaly occurs most often in infants of four months age or younger because (i) the skulls of young infants are still easily deformed; (ii) the posterior calvaria are rapidly expanding against a flat surface; and (iii) such infants are neuromuscularly immature and lack the coordination to shift their head position. If left uncorrected, the pressure forces will likely remain continuously applied until the infant reaches 6-8 months of age, whereupon the existing deformation will likely become permanent.
Infants with torticollis (wry neck) are particularly at risk for posterior plagiocephaly since their condition will make them favor turning their head one way. By definition, torticollis is a congenital or acquired condition of limited neck motion in which the child will hold the head to one side with the chin pointing to the opposite side; and is the result of the shortening of the sternocleidomastoid (neck) muscle. Thus, as a consequence of the positioning of the head continually in one side position, the infant suffers from the flattening of that side of his head. This asymmetrical plagiocephaly is particularly disfiguring in appearance.
It as been recognized that the vast majority of infants with occipital flattening do not have Craniosynostosis—a premature obliteration of the sutures which results in skull deformity and potential restricted growth of the brain. Also, Lamboid Synostosis, which can mimic deformational posterior plagiocephaly, is remarkably rare, occurring only in an estimated 20 per million live births. Thus, occipital flattening is about 5000-8000 times more likely to occur from a deformation process than from a sutural fusion.
Incidence of Posterior Plagiocephaly:
The incidence rate of posterior plagiocephaly in some infant populations can be as high as 48%. By contrast, the incidence rate of craniosynostosis is only about 1 in 3,000 infants [Bruneteau, R J. & J. B. Mulliken, “Frontal Plagiocephaly: Synostotic, Compensational, Or Deformational”, Plastic and Reconstructive Surgery 89(1):21-31 (January 1992)].
Actual incidence rates vary by patient population and age; and will be influenced by cultural habits for positioning resting newborns. Also, as with all diseases, the severity of the posterior plagiocephaly comes in degrees. Nevertheless, any kind of plagiocephaly is very unnerving for parents to live with.
Research at Children's Hospital and Harvard Medical School in 2002 by Dr. Peitsch and others indicated that 13% of all single-birth newborns and 56% of all twins had localized cranial flattening, a possible precursor to posterior plagiocephaly [Peitsch et al., “Incidence of Cranial Asymmetry in Healthy Newborns”, Pediatrics 110(6):e72 (December 2002)]. A further 10% of all infants suffer from congenital torticollis, which will exacerbate a tendency towards posterior plagiocephaly.
Furthermore, about 25,000 infants are referred to us specialists every year for treatment from plagiocephaly. With 4.6 million live births in the U.S. annually, there are likely to be at least 600,000 infants born each year in need of corrective treatment for plagiocephaly; and prophylactic measures to prevent or avoid deformational posterior plagiocephaly would benefit all newborns.